Herbicidal compositions based on 1,2,3-thiadiazol-5-yl ureas

ABSTRACT

A new class of herbicidal compounds of the formula:   WHERE A is lower alkyl or alkenyl radical, B is -H or -CH3, X is oxygen or sulfur, and Y is an alcohol or amine residue, and the metallic and amine salts thereof, has selective pre-emergence and post-emergence herbicidal activity. The synthesis of members of this class is described in detail, and the utility of representative compounds is exemplified.

United States Patent [191 Volpp et al.

[ Apr. 1, 1975 1 HERBICIDAL COMPOSITIONS BASED ON 1,2,3-THIADIAZOL-5-YL UREAS [75] Inventors: Gert Paul Volpp, Princeton; Harry Dounchis, Lawrence, both of NJ.

[73] Assignee: FMC Corporation, New York, NY.

[22] Filed: May 7, 1973 [21] Appl. No.: 357,611

Related U.S. Application Data [60] Division of Ser. No. 238,664, March 27, 1972, Pat.

No. 3,787.434, which is a continuation-in-part of Ser. No. 156.125,.1unc 23, 1971, abandoned.

3,734,923 5/1973 Dowding et al 71/90 Primary Examiner-Glennon 1'1. Hollrah [57] ABSTRACT A new class of herbicidal compounds of the formula:

0 u 11 C-Y u N N-C-N-A \s 1 I I "X B where A is lower alkyl or alkenyl radical, B is H or -C1-l X is oxygen or sulfur, and Y is an alcohol or amine residue, and the metallic and amine salts thereof, has selective pre-emergence and postemergence herbicidal activity. The synthesis of members of this class is described in detail, and the utility of representative compounds is exemplified.

4 Claims, No Drawings HERBICIDAL COMPOSITIONS BASED ON where A is lower alkyl or alkenyl radical of up to four 1.2,3-THIADIAZOL--YL UREAS carbon atoms; B is H or --Ch with the proviso that B is H when A is other than CH X is oxygen or CROSS REFERENCE TO RELATED I APPLICATIONS 5 sulfur, Y 15 OR, NHR, NRR NB NH or This is a division of application Ser. No. 238,664, filed Mar, 27, 1972, now US. Pat. No. 3,787,434, -n' which application is a continuation-in-part of application Ser. No. 156,125, filed June 23, 1971, now abandoned. in which R and. R are alkyl, alkenyl, alkynyl or cycloal- This invention pertains to the general field of herbikyl groups containing up to 12 carbon atoms which cides, and particularly to compositions which selecmay contain an ether linkage or a hydroxy substituent, tively control plant growth. and in which R and R may be the same or different; Z There is a substantial need for herbicides with selecis O, -Ch or absent. Metallic and amine salts tively in both preand post-emergence applications. It 15 of these novel compounds show similar herbicidal acis known that certain substituted 1,2,4- and 1,3,4- tivity; agriculturally acceptable metallic cations, such thiadiazoles and urea derivatives thereof exhibit herbias sodium, potassium, ammonium, calcium and zinc, cidal activity of varying types. However, the outstandmay be employed. ing plant responses in selective pre-emergence and Procedures by which the compounds of this invenpost-emergence herbicidal activity of the compounds tion may be prepared are exemplified by one or more of the present invention have not previously been re- 0f t e f l ing: ported or suggested in the art. a. aminolysis of phenyl (thiadiazol-S-yl)carbamates:

0 0 l l N -OR N C-OR ll (sl ll N u-c-o-r! N\ N-C-N-Cll S I ll l [L l a o H CH This invention pertains to novel herbicidal comb. aminolysis of 1-substituted-3-(4-alkoxycarbonylpounds, to new herbicidal compositions, and to new l,2,3-thiadiazol-5-yl)ureas:

O 0 l l -OR N -R' ll fl R'Nn ut")- N N-c-N-cn 75* N\ --c--N-cn I II I S I ll l H 0 CH3 n 0 CH3 methods for the selective control of undesired plant 0. ester exchange of 1-substituted-3-(4-alkoxygrowth. Particularly useful control of undesired plant carbonyl-l,2,3-thiadiazol-5-yl)ureas:

N -oR' N -OR" won N\ s T-(i-N-R N\ s N-C-N-R o l l Ell growth is obtained in the presence of such crops as d. via S-(S-substituted ureido)-1,2,3-thiadiazol-4- corn and peanuts. Said compositions may be applied carbonyl chloride:

' o o N i'i-cl N i y l 4 I I l N -N-C-NR N N-C-N-R llll \s Ill n o R H o R and utilized by commonly accepted methods. Thioureas may be prepared from the corresponding The new herbicidal compositions of this invention ureas by reaction with phosphorus pentasulfide. Salts are of the formula: may be prepared by reaction of the urea with an appropriate base. i The phenyl (4-alkoxycarbonyl-l ,2,3-thiadiazol-5-yl)- N 4 c Y carbamates necessary for the preparation of the comll g 2 pounds of this invention according to method (a) N c N A above have been prepared accordin to the eneral a g S s 5 l u procedure of Goerdeler and Gnad [Chem. Ber. 99,

a x B 1618 (1966) Using that method, 78.25 g of phenyl chloroformate was added to a suspension of 48.5 g of potassium thiocyanate in 100 ml of acetonitrile containing 57.0 g of ethyl diazoacetate. The mixture was stirred for 25 hours, then poured into 500 ml of water. The red solid was collected, washed with ethanol and recrystallized, with charcoal treatment, from ethanol to give 37 g (26 percent) of yellow crystalline solid. A second recrystallization, with charcoal treatment, from ethanol gave 26 g (18 percent) of phenyl (4- ethoxycarbonyl- 1 ,2,3-thiadiazol-5-yl)carbamate, white leaflets, mp 154155 (Goerdeler and Gnad report mp 156C).

Using the appropriate diazoacetates, phenyl (4- propoxycarbonyl-l ,2,3-thiadiazol-5-yl) carbamate (mp l38l39.5C) and phenyl (4-butoxycarbonyl-1,2,3- thiadiazol-S-yl)carbamate (mp 127.5-128C) were similarly prepared, in yields of 28 and 8 percent respectively.

The preparation of representative members of this class of herbicidal compounds is illustrated below. All temperatures are expressed in degrees centigrade. All parts and percentages are by weight.

EXAMPLE 1 Preparation of 1 ,1 -Dimethyl-3-(4-ethoxycarbonyll,2,3-thiadiazol-5-yl)urea Intoa 250 ml flask equipped with condenser, stirrer and gas bubbler were placed 2 g of phenyl (4- ethoxycarbonyl-l,2,3-thiadiazol-5-yl) carbamate and 100 ml of chloroform. Dimethylamine gas was bubbled through the solution for a period of 10 minutes at room temperature, at which time the reaction was shown to be complete by thin-layer chromatographic analysis. The solvent was removed and the residue recrystallized from ethanol to give 1.1 g of l,1-dimethyl-3-(4- ethoxycarbonyl-l ,2,3-thiadiazol-5-yl)urea, mp l56-l57. Recrystallization again from ethanol increased the melting point to 159-161. The nmr spectrum was consistent with the assigned structure.

Analysis: Calc'd for CBHI2N4O3SZ C 39.34; H 4 Found: C 39.15; H 4.88;

EXAMPLE 2 Preparation of 1-Methyl-3-(4-ethoxycarbony1-1 ,2,3- thiadiazol-S -yl )urea By the procedure of Example 1, methylamine was bubbled through a mixture of 10 gof phenyl (4- ethoxycarbonyl-1,2,3-thiadiazol-5-yl) carbamate in chloroform for minutes. After removal of the solvent, the product was recrystallized from ethanol (using charcoal) to give 3g of 1-methyl-3-(4- ethoxycarbonyl- 1 ,2,3-thiadiazol-5-yl )urea; mp 230-231.

An additional 1.8 g of product was obtained by the.

same reaction, using 5g of starting carbamate. The product was recrystallized several times to obtain product melting at 233.5234.5. A mixture of these two samples was employed in the herbicidal studies.

Analysis: Calcd for C,H ,N.,O S: C 36.52;

Found: C 36.57;

EXAMPLE 3 Preparation of 1 l -Dimethyl-3-(4-propoxycarbonyll,2,3-thiadiazol-5-yl)urea I By the procedure of Example 1, dimethylamine was reacted for 4 hours with 3.0 g of phenyl (4- propxycarbonyll ,2,3-thiadiazol-5-yl)carbamate in ml of chloroform, maintaining the temperature of the reaction mixture below 35. The solvent was removed under reduced pressure and the residue was pu-. .rified by chromatography on alumina to give 1.5 gof l,1-dimethyl-3-(4-propoxycarbonyl1,2,3-thiadiazol-5- Analysis: Calcd for C H MO S: 041.86; H 5.46; N

Found: C 41.19; H 5.43; N

Using an alternate synthetic procedure, another sample was prepared for use in herbicidal testing. A chip of sodium metal (catalytic amount) was added to 300 m1 of n-propanol and to the solution was added 7.0 g of 1 ,1 -dimethyl-3-(4-ethoxycarbonyl-1 ,2,3-thiadiazol- 5-yl)urea. The reaction mixture was heated under re-. flux (97) overnight. A thin-layer chromatographic analysis indicated the reaction was complete. The mix ture was cooled to 0 and the solid collected by filtratron to give 44.3 g of 1,1-dimethy1-3-(4- propoxycarbonyl-l ,2,3-thiadiazol-5-yl )urea;

sistent with the assigned structure.

EXAMPLE 4 preparation of 1, l -Dimethyl-3-( 4butoxyearbonyl-.

1 ,2,3-thiadiazol-5-yl)urea A solution of 4.40 g of phenyl (4-butoxycarbonyl- 1,2,3-thiadiazol-5-yl)carbamate in 50 ml ofchloroform g i was treated with 0.68 g of dimethylamine in 25 ml of i chloroform and the mixture was kept at ambient temperature. After 24 hours, a slight excess of dimethylamine was passed through the mixture. The solvent was removed under reduced pressure and the residue, was triturated with 5 percent of ether in petroleum ether to give 3.37 g of product. The product was recrystallized twice from petroleum ether to give 1.83 g of 1,1-: I

dimethyl-3-(4-butoxycarbonyl-1,2,3-thiadiazol-5- yl)urea; mp 80.881.5. The ir spectrum of the prod- I uct was consistent with the assigned structure Analysis: Calcd for C H N O S: C 44.11; H 5

Found: C 44.03; H 5.81;

EXAMPLE 5 p .=1 120.5l22. The ir spectrum of this product was con-,

1,1-dimethyL3-(4- residue triturated with hot water. The solid was dried overnight under reduced pressure to give 2.5 g of 1,1- dimethyl-3-( 4-isobutoxycarbonyl-l ,2,3-thiadiazol-5 yl)urea; mp 1 19-l2l. The ir and nmr spectra were consistent with the assigned structure.

Analysis: Calcd for C H N O S: C 44.11;

Found: C 44.09;

EXAMPLE 6 Preparation of l,l-Dimethyl-3-(4-isobutylcarbamoyll,2,3-thiadiazol-5-yl)urea A mixture of 7.0 g of l,l-dimethyl-3-(4- ethoxycarbonyl-l,2,3-thiadiazol-5-yl)urea and 100 ml of isobutylamine was refluxed for 3 hours. The mixture was set aside overnight at ambient temperature and was then concentrated under reduced pressure. The residue was stirred with 100 ml of 10 percent acetic acid, cooled by filtration, washed with water and vacuumdried over phosphorus pentoxide. The product was recrystallized from heptane and vacuum-dried at 40 over phosphorus pentoxide to give 5.70 g of 1,1-dimethyl-3- (4-isobutylcarbamoyll,2,3-thiadiazol-5-yl)urea; mp l l7l 18. The ir and nmr spectra of the proeuct were consistent with the assigned structure.

Analysis: Calcd for C H N O S: C 44.27; H 6.32; N 25.82

Found: C 44.94; H 6.62; N 25.29.

EXAMPLE 7 preparation of l,1-Dimethyl-3-(4-decylcarbamoyll,2,3-thiadiazol-5-yl)urea A mixture prepared from 7.0 g of l,l-dimethyl-3-(4- ethoxycarbonyl-l,2,3-thiadiazol-5-yl)urea and 50 ml of n-decylamine (exothermic) was heated until a single phase resulted. The reaction mixture was then cooled and poured into 600 ml of petroleum ether. The insoluble product was collected by filtration and washed with petroleum ether. Additional product, obtained by concentration of the petroleum ether filtrate, was washed several times and combined with the first crop of product. The product was stirred for 20 minutes with 150 ml of 20 percent acetic acid, collected by filtration, washed and dried. The product was then recrystallized from heptane and vacuum-dried over phosphorus pentoxide to give 5.51 g of l,l-dimethyl-3-(4-decylcarbamoyl-l ,2,3-thiadiaZol-5-yl) urea; mp=8586.3. The ir and nmr spectra of the product were consistent with the assigned structure.

Analysis: Calcd for C H N O S: C 54.06; H 8.22; N l9.7l

Found: C 54.30; H 8.58; N l9.38.

EXAMPLE 8 chromatographic analysis indicated no reaction and the mixture was heated under reflux overnight. The mixture was cooled, volatile materials removed under reduced pressure and the residue was recrystallized twice from heptane to give 2.0 g of l,l-dimethyl-3-(4- isopropylcarbamoyl- 1 ,2,3-thiadiazol-5 -yl )urea, .mp l53.5l55.5. The ir and nmr spectra of the product were consistent with the assigned structure. Recrystallization from isopropanol gave solid, mp l53l54.

Analysis: Calcd for C H,,,N,,O S: C 42.02; H 5.88; Found: C 4|.84; H 6.30;

EXAMPLE 9 Preparation of 1,1-Dimethyl-3-(4-butylcarbamoyll,2,3-thiadiaz0l-5-yl)urea A solution of 5.0 g of l,l-dimethyl-3-(4- ethoxycarbonyl-l ,2,3-thiadiazol-5-yl)urea in ml of butylamine was heated under reflux for 2.5 hours, then cooled and filtered. Removal of the volatile materials left a yellow oil which crystallized on trituration with ethyl ether. The solid was collected and recrystallized from octane to give solid, mp lll-l20. The ether wash was concentrated to give a solid, mp 128l40. These two solids were separately recrystallized from cyclohexane to give solids, mp l30l3 1 The combined yield of l,l-dimethyl-3-(4-butylcarbamoyll,2,3-thiadiazol-5-yl)urea was 3.2 g. The ir and nmr spectra of the product were consistent with the assigned structure.

Analysis: Calcd for C H N O S: C 44.27; H 6.32; N 25.82

Found: C 43.80; H 6.50; N 25.27.

EXAMPLE 10 Preparation of l l -Dimethyl-3-(4-sec-butylcarbamoyl- 1,2,3-thiadiazol-5-yl )urea A solution of 4.0 g of l,l-dimethyl-3-(4- ethoxycarbonyl-l,2,3-thiadiazol-5-yl)urea in 50 ml of sec-butylamine was heated under reflux overnight. The volatile materials were removed under reduced pressure and the residual yellow oil triturated with ethyl ether and petroleum ether to give 3.9 g of solid, mp l20.4l23. This crude product was washed with dilute hydrochloric acid, then recrystallized twice from heptane, then from butanol, to give 1.9 g of 1,1- dimethyl-3-(4-sec-butylcarbamoyl-1,2,3-thiadiazol-5- yl)urea, mp l3ll32. Recrystallization from ethanol increased the melting point to l32133. The ir and nmr spectra of the product were consistent with the assigned structure.

Analysis: Calcd for C H,-,N,,O,S: C 44.27; H 6.32; N 25.82

Found: C, 44.54; H 6.58; N 26.09.

EXAMPLE ll Preparation of l,1-Dimethyl-3-(4-allylcarbamoyll ,2,3-thiadiazol-5 -yl )urea Analysis: Calcd for C I-1, 19,0 C 42.35; H 5.13; N 27.44 Found: C 42.55; H 5.53; N 26.91

EXAMPLE 12 Preparation of l,l-Dimethyl-3-(4-methallylcarbamoyl- 1,2,3-thiadiazol-5-yl )urea A mixture of 5.0 g of 1,1-dimethyl-3-(4- ethoxycarbonyl-l,2,3-thiadiazol-5-yl)urea and g of methallylamine was heated for 5 hours. Decolorizing charcoal was added and the reaction mixture was fil-.

tered ;through a layer of diatomaceous earth, rinsing the filter with chloroform. The filtrate was concentrated under reduced pressure and the residue was washed'with ether to give 5.5 g of solid, mp l30135. Recrystallization from acetonitrile gave 2.7 g of l ,l-dimethyl-3-(4-methallylcarbamoyl-l ,2,3- thiadiazol-5-yl)urea, mp l3l37. Recrystallization from benzene increased the melting point to l35l37.

Analysis: Calcd for c u mo sz C 44.60; H 5.62; N 26.01

Found: C 44.45; H 5.34; N 26.18.

EXAMPLE 1 3 Preparation of l ,1-Dimethyl-3-]4- (dimethylcarbamoyl l ,2,3-thiadiazol-5 -yl ]urea During 4 hours, dimethylamine gas was bubbled through a solution of 1.0 g of phenyl (4- ethoxycarbonyl-l ,2,3-thiadiazol-5-,yl )carbamate in 8 ml of dimethylformamide. The reaction mixture was poured into ice water and allowed to stand overnight at room temperature. The mixture was extracted with three ISO-ml volumes of methylene chloride; and the.

extracts were combined, washed with water and dried over magnesium sulfate. Solvent was removed under reduced pressure to give a yellow oil which upon trituration with ethanol, using a dry-ice bath, gave 0.3 g of solid product, mp= l30l40. Two recrystallizations from ethanol gave purified 1,1-dimethyl-3-[4- (dimethylcarbamoyl)-l ,2,3-thiadiazol-5-yl]urea; mp 158-l 59. The ir and nmr spectra were consistent with the assigned structure.

Analysis: Calcd for C H MO S: C 39.50; H 5.

Found: C 39.62; H 5.

In the same manner, 10 g of phenyl (4- ethoxycarbonyll ,2,3-thiadiazol-5 -yl )carbamate in 65 ml of dimethylformamide was saturated with dimethylamine for five hours at steam-bath temperature. Isolation of the product as above gave, after recrystallization from ethanol, 2.3 g of 1,1-dimethyl-3-[4- (dimethylcarbamoyl)-1,2,3-thiadiazol-5-yl]urea, mp

15 8 .5-l 59.5. Mixture with the product previously obtained resulted in no depression of the melting point.

EXAMPLE 14 Preparation of 1 l -Dimethyl- 3-( 4-- morpholinocarbonyl-l ,2,3 -thiadiazol-5-yl )urea A mixture of 7.0 g of 1,1-dimethyl-3-(4- ethoxycarbonyl-l,2,3-thiadiazol-5-yl)urea and 2.1 g of morpholine in 100 ml of ethanol was heated underreflux for 20 hours. Thin-layer chromatographic analysis 7 indicated no reaction, thus volatile materials were removed and 50 ml of morpholine was added to the residue. This mixture was heated ona steam bath .for 2 hours, after which thin-layer chromatographic analysis indicated complete reaction. Unreacted morpholine was removed under reduced pressure and the residue washed with ether. The washed solid was recrystallized from ethanol to give, after drying over phosphorus. pentoxide, 5.8 g of l ,1-dimethyl-3-(4- morpholinocarbonyl-l ,2,3-thiadiazol-5-yl)urea; mp l65-166. A second recrystallization increased the melting point to 166.3167. The ir and nmr spectra were consistent with the assigned structure.

Analysis: Calcd for c n u o s: C 42.10; .55

Found: C 1.86; H 42; 24.27;

EXAMPLE 15 Preparation of l,l-Dimethyl-3-(4-carbazoyl-1,2,3-

thiadiazol-S-yl) urea To 50 ml of percent hydrazin hydrate was adde portionwise 7.0 g of l,1-dimethyl-3 (4-ethoxycarbonyll,2,3-thiadiazol-5-yl)urea. The mixture was heated to about 50, after which hydrazine hydrate was removed under reduced pressure. The product was recrystallized I from aqueous alcohol (50 percent) and vacuum-dried over phosphorus pentoxide to give 3.66 g of 1,1.- dimethyl-3-(4-carbazoyl-l ,2,3-thiadiazol-5-yl )urea;

m =220.5222 The ir and nmr spectra were con- 1 I sistent with the assigned structure.

Analysis: Calcd for C,H, N,O S: C 31.31; 4.36;

H FOUDCILC 31.35; H

EXAMPLE 16 Preparation of l-Methyl-3-.( 4-isopropylcarbamoyl- 1,2,3-thiadiazol-5-yl )urea A mixture of 5.0 g of l-methyl-3-(4-ethoxycarbonyll,2,3-thiadiazol-5-yl)urea and 60 ml of isopropylamine. was stirred at ambient temperature for 19 hours, after which thin-layer chromatographic analysis indicated that all starting urea had been consumed. The solid was isolated and the filtrate concentrated to give another a solid. The two solids were independently washed with dilute hydrochloric acid and recrystallized from acetonitrile to give crystals which melted at l84-187. Infrared spectroscopic examination showed the two solids to be identical; thus they were combined to give 2.9 g of A 1-methyl-3-(4-isopropylcarbamoyl-1 ,2,3-thiadiazol-- yl)urea. The nmr spectrum was consistent with the assigned structure.

Preparation of thiadiazol-5-yl)urea By the method of Example 4, g of phenyl (4- ethoxycarbonyl-l ,2,3-thiadiazol-5 -yl )carbamate was dissolved in 150 ml of chloroform, and to the solution was added during /2 hour a solution of 1.85 g of ethylamine in 100 ml of chloroform. After the mixture was stirred at room temperature for about 72 hours, thinlayer chromatographic analysis indicated that reaction was incomplete. Precipitated solid was removed by filtration, a few drops of ethylamine were added to the filtrate, and stirring was continued for 24 hours. Thinlayer chromatographic analysis again showed the reaction was incomplete. After removal of solid and addition of several drops of ethylamine to the filtrate, stirring was continued for an additional 24 hours, after which thin-layer chromatographic analysis showed the reaction to be complete. The reaction mixture was concentrated under vacuum to yield a solid which was washed with ether. The filtered solids and that recovered from the solvent were combined and recrystallized from ethanol to give a total of 4.65 g of l-ethyl-3-(4- ethoxycarbonyl-l ,2,3-thiadiazol-5-yl)urea; mp 225.5 226. The ir, nmr and mass spectra of the product were consistent with the assigned structure.

1-Ethyl-3-(4-ethoxycarbonyl-1 ,2,3-

Analysis: Calcd for C..H, N.,o,s: C

Found: C 39.49;

EXAMPLE 18 Preparation of 1 l -Dimethyl-3-]4-( methyl- (isopropyl )carbamoyl-l ,2,3-thiadiazol-5-yl ]urea To a solution of 13.4 g of potassium hydroxide in a mixture of 600 ml of ethanol and 200 ml of water was added 53 g of 1,1-dimethyl-3-(4-ethoxycarbonyl-l ,2,3- thiadiazol-5-yl)urea (Example 1). This mixture was heated under reflux for 18 hours, then treated with activated charcoal and filtered. The solvent was removed by distillation under reduced pressure. The solid residue was dissolved in ice water. Addition of dilute hydrochloric acid gave a precipitate which was collected on a filter, washed with water, and dried to yield 41.3 g of 5-(3,3-dimethylureido(-l ,2,3-thiadiazole-4- carboxylic acid; mp l93-l97. (Recrystallized from acetonitrile, the product melted at 205.) After the acid, mixed with 450 ml of thionyl chloride, was heated under reflux for 45 minutes, the excess thionyl chloride was removed by distillation under reduced pressure. The resulting acid chloride was dissolved in sufficient methylene chloride to give a total volume of 300 ml of solution, which was used in thenext step without further purification.

(In another preparation, 5-(3,3-dimethylureido)- l,2,3-thiadiazole-4-carbonyl chloride was isolated as a yellow-brown crystalline solid, mp 120-125, which tended to decompose on standing.)

Fifty milliliters of the methylene chloride solution described above was added to a solution of 2.5 g of (methyl)-(isopropyl)amine in 50 ml of methylene chloride. The mixture was allowed to stand for 2 hours, washed successively with water and dilute hydrochloric acid, and then dried over sodium sulfate. After the solvent was removed under reduced pressure, the residue was washed with petroleum ether and recrystallized twice from cyclohexane to give 3.81 g of 1,1-dimethyl- 3-[4-(methyl)(isopropyl)carbamoyl-1 ,2,3-thiadiazol- 5-yl]urea; mp l21123.

Analysis: Calcd for c, H,,N,o,s; C 44.27; H 6.32; N 25.82

Found: C 44.13; H 6.10; N 25.96.

EXAMPLE 19 Preparation of the Sodium Salt of 1,1-Dimethyl-3-(4- and the washed solid was recrystallized from acetonitrile to give 4.2 g of the sodium salt of 1,1-dimethy1- 3- (4-isobutylcarbamoyl-l ,2,3-thiadiazol-5-yl)urea; mp 260 (decomposed). After two more recrystallizations, the melting point was 290. The ir and nmr spectra were consistent with the assigned structure.

1,2,3-thiadiazol-5-yl)urea A mixture of 5.0 g of l-methyl-3-(4-ethoxycarbonyl- 1,2,3-thiadiazol-5-yl)urea (Example 2) and 60 ml of isobutylamine was stirred about 16 hours at room temperature. The excess isobutylamine was removed by evaporation under reduced pressure to leave a yellow solid. The filtrate and the solid residue were worked up separately.

The solid was triturated with ml of methylene chloride and the isoluble solid isolated by filtration. The filtrate was concentrated to give a solid residue which was washed first with dilute hydrochloric acid, then with water. Recrystallization from acetonitrile gave 1 -methyl-3-(4-isobuty1carbamoyl-1 ,2,3- thiadiazol-5-yl(urea; mp l72-174. The ir and nmr spectra were consistent with the assigned structure.

The methylene chloride-insoluble solid was determined by ir and nmr spectra to be the isobutylamine salt of the desired urea. Treatment of this solid with dilute hydrochloric acid gave a product (mp l72174 after recrystallization from carbon tetrachloride) identical with that obtained from the filtrate as described above.

Analysis: Calcd for cm,,N,o,s: C 42.02; H

Found: C 42.11; H

The reaction was repeated, using 39 g of l-methyl-3- (4-ethoxycarbonyl-l,2,3-thiadiazol-5-yl)urea and 300 ml of isobutylamine. The excess amine was removed and the residue was stirred for minutes with 150 ml of 5 percent hydrochloric acid. The solid was collected on a filter and washed with water. The washed solid was stirred with 400 ml of chloroform and then filtered. The filtrate was processed as described above to give 29.55 g of white solid, mp l70172, the nmr spectrum of which varied slightly from that of the previously described product and indicated the solid to be a hydrate. The treatment with dilute hydrochloric acid was repeated without change in spectrum, but recrystallization of the solid from benzene gave 20.55 g of product identical with that described above.

The chloroform-insoluble solid from above was recrystallized from acetonitrile to give the isobutylamine salt of 1-methy1-3-(4-isobutylcarbamoy1-l ,2,3- thiadiazol-5-yl)urea; mp l71173.

Analysis: Calcd for C H N O S: C 47.26;

H 7.93; Found: C 47.34; H

EXAMPLE 21 Analysis: Calc'd for C H N OS C 39.56; Found: C 39.75;

EXAMPLE 22 Preparation of lEthyl-3-(4-isobutylcarbamoyl-l ,2,3- thiadiazol-5-yl)urea A mixture of 5.0 g of 1-ethy1-3-(4-ethoxycarbonyll,2,3-thiadiazol-5-yl)urea (Example 17 in 100 ml of isobutylamine was stirred for about hours at ambi ent temperature and then concentrated under reduced pressure. The residue was stirred for 30 minutes with 120 ml of water containing 6 ml of hydrochloric acid. The undissolved solid was isolated, washed with water,

and then dissolved in chloroform. The chloroform solution was dried (MgSO and concentrated. The residual solid was recrystallized twice from benzene to give 3.5 g of 1-ethyl-3-(4-isobutylcarbamoyl-1,2,3-thiadiazol-5- yl)urea; mp l52l53. The ir spectrum was consistent with the assigned structure.

Analysis: Calcd for C,,,H, N O,S: C 44.27; H 6.

Found: C 44.14; H 6.

EXAMPLE 23 Analysis: Calcd for C H N O S: C 42.35; H

5.13, Found: C 41.74; H 5

EXAMPLE 24 Preparation of 1-Methyl-3-(4-isopropylcarbamoyl l,2,3-thiadiazol-5-yl)urea (Example 16) was reacted with 5.8 g of phosphorus pentasulfide in 250 ml of1diox-.

ane. The reaction mixture was decanted from the insoluble material present (free sulfur) to give a solution which was treated with charcoal, filtered, andconcen-i trated under reduced pressure. The residue was dis- I solved in ethanol, filtered, and again concentrated. under reduced pressure. The residue was recrystallized from carbon tetrachloride to give 0.6 g of l-methyl-3- (4-isopropylcarbamoyl-1 ,2,3-thiadiazol-5 -yl )-2- thiourea, mp l8l-183.5. The ir and mass spectra were consistent with the assigned structure.

Analysis: Calcd for C H,;,N OS C 37.07;

Found: C 37.15;

EXAMPLE 25 Preparation of lIsopropyl-3-(4-isopropylcarbamoyl l ,2,3-thiadiazol-5-yl)urea A mixture of 8 g of phenyl (4-ethoxycarbony1-l,2,3- thiadiazol-S-yl)carbamate and ml of isopropylamine was stirred at ambient temperature for 28 hours. The excess isopropylamine was evaporated under reduced pressure and the residual semisolidwas washed with 200 ml of benzene. The insoluble solidwas slurried with water and acidified with 5 percent hydrochlo-w ric acid. The solid was isolated on a filter and dissolved. in chloroform. The chloroform solution was dried (MgSO and solvent removed to yield 3.79 g of white solid, mp l78-l-81. Recrystallization from benzene gave 2.67 g of l-isopropy1-3-(4-isopropylcarbamoyl- 1,2,3-thiadiazol-5-yl)urea, mp=182185; The ir and nmr spectra were consistent with the assigned.

structure.

Analysis: Calc'd for c,.,r-i,,N,o,s= C 44.27;

Found: C

Additional compounds which have been prepared, and which have shown herbicidal activity, includethe following 4-substituted compounds of 1,1-dimethyl-, l-alkyl-, l-alkenyland 1-alkoxy-3-(l,2,3{thiadiazol-5 yl)urea, listed with rnelti'rigpoin'ts in degrees centi- 1-Methy1-3-(4-methallylcarbamoylr.

(Example N 27. .03;N 27. l

size, asa wettable powder, as an emulsifiable concentrate, as a solution, or as any of several other known types of formulations, depending on the desired mode of application.

Granular formulations are particularly useful for aerial distribution or for penetration of a canopy of foliage. Useful granular formulations may be of several types. impregnated granules are those wherein the active ingredient is applied to large particles of an absorbent carrier, such as an attapulgite or kaolin clay, corncobs, expanded mica, etc., normally in the form of a solution in a solvent. Surface-coated granules may be produced by spraying the molten active ingredient onto the surface of a generally nonabsorbent particle or by spraying on a solution of active ingredient in a solvent. The core may be water-soluble such as prilled fertilizer, or insoluble such as sand, marble chips or coarse talc. Particularly useful is a granule wherein a wettable powder is applied as a surface coating to a sand or other insoluble particle such that the wettable powder may be dispersed on contact of the granule with moisture. Granules may be produced by agglomeration of dusts or powders by compaction rollers, by extrusion through a die or by use of a granulating disc. Granular formulations may vary widely in concentration, with useful formulations containing as little as 0.5 percent or as much as 95 percent of active ingredient.

wettable powders, also useful formulations for both preand post-emergence herbicides, are in the form of finely divided particles which disperse readily in water or other dispersants. The wettable powder is ultimately applied to the soil either as a dry dust or as an emulsion in water or other liquid. Typical carriers for wettable powders include fuller's earth, kaolin clays, silicas and other highly absorbent, readily wet inorganic diluents. wettable powders normally are prepared to contain about to 80 percent of active ingredient, depending on the absorbency of the carrier, and usually also contain a small amount of a wetting, dispersing or emulsifying agent to facilitate dispersion. For example, a useful wettable powder formulation. contains 80.8 parts of a thiadiazolylurea of this invention, 17.9 parts of palmetto clay, and 1.0 part of sodium lignosulfonate and 0.3 part of sulfonated aliphatic polyester as wetting agents.

Other useful formulations for herbicidal applications are the emulsifiable concentrates, which are homogeneous liquid or paste compositions dispersible in water or other dispersant, and may consist entirely of a thiadiazolylurea of this invention with a liquid or solid emulsifying agent, or may also contain a liquid carrier, such as xylene, heavy aromatic naphthas, isophorone and other nonvolatile organic solvents.

Typical wetting, dispersing or emulsifying agents used in agricultural formulations include, for example, the alkyl and alkylaryl sulfonates and sulfates and their sodium salts; polyethylene oxides; sulfonated oils, fatty,

acid esters of polyhydric alcohols; and other types of surface-active agents, many of which are available in commerce. The surface-active agent, when used,;normally comprises from 1 to 15 percent by weight of the herbicidal composition.

Other useful formulations for herbicidal applications 3 include simple solutions of the active ingredient in a dispersant in which it is completely soluble at the de-.

sired concentration, such as acetone or other organic solvents. These formulations may be applied without further dilution or as dilute solutions, emulsions or suspensions in water or other suitable diluent. The compositions may be applied to the area wherein control is desired by spraying onto the undesired vegetation or onto,

the surface of the soil in the case of liquid compositions Y i applications, as illustrated in the following examples:

EXAMPLE 26 Selective Herbicidal Activity I The post-emergence herbicidal activity of l-alkyland 1,l-dimethyl-3-(l,2,3-thiadiazol-5-yl)urea, and of l-methyl-3-( l ,2,3-thiadiazol-5-yl)-2-thiourea with various substituents in the 4-position on the thiadiazol ring was demonstrated as follows: Test crop seeds of Lima beans (Phaseolus lunatus), corn (Zea mays), lettuce (Lactuca sativa), mustard (Brassica juncea), and crabgrass (Digitaria sanguinalis) were planted in 8 6 3 inch shallow flat-bed trays containing 2 to 3 inches of a loam soil. The growthtrays were maintained in a greenhouse and regularly watered for approximately 2 weeks. When the first trifoliate leaves of bean plants were unfolding, the test plants were removed from the greenhouse and sprayed with an aqueous-acetone (lzl solution of the candidate herbicide containing 'l,500 ppm of active ingredient at a rate equivalent to gal lons per acre. This corresponds to one pound of active ingredient per acre. The plants were maintained in the greenhouse and regularly watered for an additional 2 Z weeks, after which time the phytotoxicity of the candidate herbicide was recordedin terms of percent kill. These results are shown in Table 1.

When the compound having only hydrogen at the 4- position was prepared, namely 1,l-dimethyl-3-(l,2,3- thiadiazol-5-yl)urea, mp 228C, it exhibited zero per-. cent kill against any of the five test crops, following post-emergence application at a level of 8 pounds per acre.

Table l C om ound Tested lb/Acre atl.

Selective Herbicidal Activity Post-emergence Application Lima Beans Corn Lettucel-Methyl- 3-( 4-substituted- ...where 4-substituent is:

Mustard Crabgrass i Table l-Continued Percent Kill of Test Plant Species Compound Tested Lima at 1.0 lb/Acrc Beans Corn Lettuce Mustard Crabgrass ethoxycarbonyl- 25 l00 lOO 0 methallylcarbamoyb 100 0 100 100 100 isopropylcarbamoyl- 90 0 I00 100 isobutylcarbamoyl- I00 100 100 100 l00 (butylamine salt) 100 I00 100 95 l-Methyl- 3-(4-substitutedl .2,3-thiadiazol-5-yl)- Z-thiourea ...where 4 substituent is:

isopropylcarbamoyl- 30 0 l00 l00 100 isobutylcarbamoyh I00 0 100 100 95 l-Ethyl- 3-(4-substituted- 1,2,3 -thiadiazol-5-yl urea ...where 4-substituent is:

ethoxycarbonyl- 30 O 90 90 0 isobutylcarbamoyl- 100 30 100 100 100 l-lsopropyl- 3-(4-isopropylcarbamoyl- 1,2,3-thiadiazol-5-yl urea 100 30 100 100 100 l. l -Dimethyl- 3-(4-substituted- 1,2,3-thiadiazol-5-yl urea ...where 4-substituent is:

ethoxycarbonyl- 0 0 l0() lOO 9O propoxycarbonyl- 30 0 90 90 30 butoxycarbonyll00 O 100 100 isobutoxycarbonyl- 70 100 100 100 isobutylcarbamoyl- 100 100 100 I00 100 (sodium salt) 100 0 100 100 0 decylcarbamoyl- 70 0 70 10 isopropylcarbamoyllOO 70 100 l00 100 butylcarbamoyl- 100 0 100 l00 9O sec-butylcarbamoyl- 100 O 100 W0 [00 allylcarbamoyl- 100 O lOO 100 100 methallylcarbamoyl- 100 O 100 100 dimethylcarbamoyl-* l00 0 lOO 70 (methyl)(isopropyl)- carbamoyl- 100 0 lOO 100 0 morpholinocarbonyl- 70 0 I00 100 50 carbazoyl- 0 O 100 100 80 Compound tested at 8 pounds per acre EXAMPLE 27 days after planting, a set of plants were sprayed with an aqueous-acetone (1:1) solution of 1,1-dimethyl-3-(4- isobutylcarbamoyl-l,2,3-thiadiazol-5-yl)urea at a rate corresponding to 80 gallons per acre (the 4 pounds per acre solution contained 6,000 ppm of active ingredient). The plants were maintained in the greenhouse and regularly watered for an additional 3 weeks, after which time the phytotoxicity of the compound was recorded in terms of percent kill. These results are shown in Table 2. Peanuts were uninjured even at 4 pounds, a rate at which all these important weeds were killed.

Table 2 Selective Herbicidal Activity of l,l-Dimethyl 3'(4-isobutylcarbamoyll.2,3-t iadiazol-5-yl)urea Post-emergence Application Percent Kill Test Plant 0.5 1.0 2.0 4.0

Species lb/Acrc lb/Acre lb/Acre lb/Acre Peanut 0 0 O O (Ame/xix liypogueu) Green foxtail grass 100 100 100 100 (Selaria viridis) Barnyard grass 0 80 100 Ecliilwc'hloa crusgulli Velvet leaf lOO lOO 100 100 (Abu rilon Iheuplirasti) Crabgrass 0 9O 95 95 (Digiraria sunguinalis) Annual morning-glory O 100 100 (Iponmea purpurea) Johnson grass (Sorghum Imlepense) Survivors were badly injured and will die EXAMPLE 29 EXAMPLE 28 Selective Herbicidal Activity of 1-Methyl-3-(4- Table 3 isopropylcarbamoyl-l ,2,3-thiadiazol-5-yl )urea The outstanding pie-emergence herbicidal activity of 1 -methy]-3-(4-isopropylcarbamoyl-1 ,2,3-thiadiazol-5- yl)urea was demonstrated as follows: Seeds of test plants were planted in 8 6 3 inch shallow flat-bed trays containing 2 to 3 inches of a loam soil. The growth trays were immediately sprayed with an aque ous-acetone (1:1) solution of l-methyl-3-(4- isopropylcarbamoyl-l ,2,3-thiadiazol-5-yl)urea at a rate corresponding to 80 gallons per acre (the 4 pounds per acre (the 4 pounds per acre solution c0ntaining.6,000

Selective Herbicidal Activity of 1 ,l-Dimethyl-3-(4-butylcarbamoyll,2,3-thiadiazol-5-yl )urea and I, l -Dimethyl-3-( 4-sec-butylcarbamoyl- 1,2,3-thiadiazol-5-yl )urea Post-emergence Application Survivors very badly injured and will die While the herbicidal activity of the substituted 60 ppm of active ingredient).The treated trays were mainthiadiazolylureas of this invention is particularly out-' standing when treatment is post-emergence, they are also effective against many weeds when applied as preemergence treatment. For example, 1-methyl-3-(4- isopropylcarbamoyl-l,2,3-thiadiazol-5-yl)urea was a 65 isop pyl ar a y ,3- y

demonstrated in the manner described in Example 26. Results of the preand post-emergence tests are highly active herbicide, as shown in Example 29.

tained in the greenhouse and regularly watered for 19 days, after which time the phytotoxicity of the compound was recorded in terms of percent kill.

The post-emergence activity of 1-methyl-3-(4- was shown in Table 4.

Table 4 Selective Herbicidal Activity of l-Methyl-3-( 4-isopropylcarbamoyh 1,2,3-thiadiazol-5-yl )urea Percent Kill Test Plant 0.5 1.0 2.0 4.0

Species lb/Acre lb/Acre lb/Acre lb/Acre l re-emergence Lima beans 30 100 100 100 Corn 3O 30 100 100 Lettuce 80 100 N 100 Mustard I00 100 I00 100 Crabgrass 20 100 100 100 Post-emergence Lima beans 100 90 100 100 Corn 0 O 100 100 Lettuce 100 100 100 100 Mustard 100 100 100 I00 Crabgrass 1O 20 100 [00 where A is lower alkyl or alkenyl radical of up to four carbon atoms; B is H or -CH with the proviso that B is --l-[ when A is other than CH X is oxygen or sulfur; Y is -OR, NHR, NRR', NHNH or in which R and R are alkyl, alkenyl, alkynyl, cycloalkyl, hydroxyalkyl, or alkoxyalkyl groups containing up to 12 carbon atoms, and in which R and R may be the same or different; Z is -0, CH or absent; and the agriculturally acceptable metallic and amine salts thereof;

b. an inert agricultural carrier; and

C. a surface-active agent.

2. A composition according to claim 1 in which the active compound is l, l-dimethyl-3-(4-butylcarbamoyll,2,3-thiadiazol-5-yl )urea, 1,1-dimethyl-3-(4-secbutylcarbamoyl-l ,2,3-thiadiazol-5-yl )urea, 1,1- dimethyl-3-( 4-isobutylcarbamoyl- 1 ,2,3-thiadiazol-5- yl)urea, l, l -dimethyl-3-[4-(methyl)(isopropyl )carbamoyl-l ,2,3-thiadiazol-5-yl]urea, l-methyl-3-(4- isopropylcarbamoyll ,2,3-thiadiazol-5-yl )urea, 1- methyl-3-( 4-isobutylcarbamoyl-l ,2,3-thiadiazol-5- yl)urea, 1-methyl-3-(4-methallylcarbamoyl-l ,2,3- thiadiazol-5-yl)urea, 1-ethyl-3-(4-isobutylcarbamoyl- 1,2,3-thiadiazol-5-yl )urea, or 1-isopropyl-3-(4- isopropylcarbamoyl-l ,2,3-thiadiazol-5-yl)urea.

3. A method of controlling undesired plant growth which comprises applying to the locus where control is desired a herbicidally effective amount of a compound of the formula:

0 I N C-Y El N-C-N-A \s: n I ll X B where A is lower alkyl or alkenyl radical of up to four carbon atoms; B is H or CH;,, with the proviso that B is H when A is other than CH X is oxygen or in which R and R are alkyl, alkenyl, alkynyl, cycloalkyl, hydroxyalkyl, or alkoxyalkyl groups containing up to 12 carbon atoms, and in which R and Rmay be the same or different; Z is O, CH or absent; and the agriculturally acceptable metallic and amine salts thereof.

4. A method according to claim 3 in which the compound is l, l -dimethyl-3-(4-butylcarbamoyl-1 ,2,3- thiadiazol-S-yl )urea, 1,1-dimethyl-3-(4-secbutylcarbamoyl-l ,2,3-thiadiazol-5-yl)urea, 1 ,1- dimethyl-3-(4-isobutylcarbamoyl-l ,2,3thiadiazol-5- yl )urea, 1,1-dimethyl-3-[4- (methyl isopropyl )carbamoyl-l ,2,3-thiadiazol-5 yl]urea, l-methyl-3-(4-isopropylcarbamoyl-l ,2,3- thiadiazol-S -yl )-urea, l-methyl-3-( 4- isobutylcarbamoyl-l ,2,3-thiadiazol-5-yl)urea, lmethyl-3-( 4-methallylcarbamoyl-l ,2,3-thiadiazol-5- yl )urea, 1-ethyl-3 1(4-isobutylcarbamoyl-1,2 ,3- thiadiazol-5-yl)urea or l-isopropyl-3-(4- isopropylcarbamoyl- 1 ,2 ,3-thiadiazol-5 -yl )urea.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3,87Lt,873 DATED pril 1, 975

INVENTOMS) G.P.Volpp and H.Dounchis It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, line t, change N'BNH to N'H-NH Column t, line 29, change "44.5" to ---4.45--.

Column 6, line 27, change "111" to 117 Column 7, line 54, change "15" to --154.

Column 12, line 21, after ."urea", start paragraph as follows: By the method of Example 21, 6A g of 1methyl5( tiso propylcarbamoyl1,2,B-thiadiazol-B-yl)urea--.

Column 22, line 52 (claim t) after "1-ethyl-5" substitute hyphen for "1" Signed and Scaled this twenty-first D ay Of October 1975 [SEAL] Attest:

RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner oj'Parents and Trademarks 

1. A HERBICIDAL COMPOSITION COMPRISING A. AS ACTIVE INGREDIENT, A HERBICIDALLY EFFECTIVE AMOUNT OF A COMPOUND OF THE FORMULA:
 2. A composition according to claim 1 in which the active compound is 1,1-dimethyl-3-(4-butylcarbamoyl-1,2,3-thiadiazol-5-yl)urea, 1,1-dimethyl-3-(4-sec-butylcarbamoyl-1,2,3-thiadiazol-5-yl)urea, 1,1-dimethyl-3-(4-isobutylcarbamoyl-1,2,3-thiadiazol-5-yl)urea, 1,1-dimethyl-3-(4-(methyl)(isopropyl)carbamoyl-1,2,3-thiadiazol-5-yl)urea, 1-methyl-3-(4-isopropylcarbamoyl-1,2,3-thiadiazol-5-yl)urea, 1-methyl-3-(4-isobutylcarbamoyl-1,2,3-thiadiazol-5-yl)urea, 1-methyl-3-(4-methallylcarbamoyl-1,2,3-thiadiazol-5-yl)urea, 1-ethyl-3-(4-isobutylcarbamoyl-1,2,3-thiadiazol-5-yl)urea, or 1-isopropyl-3-(4-isopropylcarbamoyl-1,2, 3-thiadiazol-5-yl)urea.
 3. A method of controlling undesired plant growth which comprises applying to the locus where control is desired a herbicidally effective amount of a compound of the formula:
 4. A method according to claim 3 in which the compound is 1,1-dimethyl-3-(4-butylcarbamoyl-1,2,3-thiadiazol-5-yl)urea, 1,1-dimethyl-3-(4-sec-butylcarbamoyl-1,2,3-thiadiazol-5-yl)urea, 1,1-dimethyl-3-(4-isobutylcarbamoyl-1,2,3thiadiazol-5-yl)urea, 1,1-dimethyl-3-(4-(methyl)(isopropyl)carbamoyl-1,2,3-thiadiazol-5-yl)urea, 1-methyl-3-(4-isopropylcarbamoyl-1,2,3-thiadiazol-5-yl)-urea, 1-methyl-3-(4-isobutylcarbamoyl-1,2,3-thiadiazol-5-yl)urea, 1-methyl-3-(4-metHallylcarbamoyl-1,2,3-thiadiazol-5-yl)urea, 1-ethyl-31(4-isobutylcarbamoyl-1,2,3-thiadiazol-5-yl)urea or 1-isopropyl-3-(4-isopropylcarbamoyl-1,2,3-thiadiazol-5-yl)urea. 